Tender for the Supply and Installation of an Open Source Electron Beam Selective Melting 3D Printer or the University of Birmingham

APPENDIX A

SPECIFICATION OF REQUIREMENTS

The University of Birmingham invites tenders for supply of an open source electron beam selective melting (EBSM) 3D printing machine. The machine will be a part of an investment by the University of Birmingham to facilitate/support the development of components for the UK's nuclear, space, and defence sectors. In this context, the machine will be used to develop new applications for the technology in collaboration with the end-users and carry out feasibility studies and pilot projects to address the specific requirements of these sectors. Therefore, it will be required as part of the project to build strong partnerships with the technology providers and define a joint co-funded R&D programme for the benefits of the UK's economy.

The machine should be capable of 3D printing refractory and structural metals and alloys using focused electron beam. The machine should allow full control on the process parameters (power/heat input, electron beam parameters, scanning strategies, materials dosing, etc...). There should be very limited restrictions on the types of materials (in powder form) that can be utilised using this platform. The system should be fully equipped with a process control interface, while being open source with respect to the process parameters. The build chamber should permit the usage of limited quantities of powders, allowing quick optimisation runs to performed and ease of cleaning following the completion of builds. The system should be flexible enough to conduct electron beam welding trials (bead on plate) or perform partial penetration on the substrate.

General characteristics

1. Electron beam

• Power: The system should be equipped with electron beam gun with a maximum power of 6 kW, with the power input being fully controllable by the user.
• Electron beam position/resolution: The electron beam size needs to be smaller or equal to 250 μm (full width -half power) for the entire beam power range.
• Electron beam speed: Electron beam deflection speed of >2000 m/s is required during 3D printing operation.
• Electron beam deflection angle: The electron beam deflection angle should cover the full build area.

2. Process chamber

• Build Volume: The system needs to have a small build volume (minimum 10 cm in diameter x 10 cm in height) for limited powder usage and quick material changeover. The build should be able to start with limited powder quantities (e.g. 1 cm height)
• Build platform carrier: Resolution of the build platform carrier in the vertical z-direction (build direction) should be 5 μm (or smaller).
• Layer thickness: The system should permit full control on powder layer thickness, including within the same build.
• Build platform heating: The build plate needs to be heated and maintain the processing temperature up to at least 1200 °C to in-situ relieve the residual stresses, while should enabling fast and efficient heating. Preheating using the electron beam should avoid interaction the powder-electron interactions (smoke-events).
• Recoater system: The recoater system should allow recoating spherical and non-spherical powders.
• Auxiliary ports: The system should have auxiliary ports to allow for in-situ instrumentation that can be integrated to the system software by the client.
• Vacuum quality: The base pressure should reach 10-6 mbar region in the main build chamber and in the electron gun, with high vacuum purity and optimum beam quality
• Process monitoring: The system should have the capability to monitor the build process using an electron back scatter detector, as well as a viewport.

3. System Software

• System source code: The system should be fully open with the code for the control software available under open-source license to allow the users to set the desired beam power and beam path to allowing for full process control for research purposes.

The preferred purchasing type for this project is on a rent-for-purchase basis with ownership transferring to the University at the end of the rental period following payment of a nominal fee. An outright purchase option is also possible.